Teses / dissertações sobre o tema "Études photochimiques"
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Bouslimani, Nouri. "Complexes mononucléaires et binucléaires à base de fer : Synthèse, études structurales, propriétés magnétiques et photochimiques". Université Louis Pasteur (Strasbourg) (1971-2008), 2008. http://www.theses.fr/2008STR13228.
Texto completo da fontePortes, Elise. "Synthèse et études de tétrahydrocurcuminoïdes : propriétés photochimiques et antioxydantes : applications à la préservation de matériaux d'origine naturelle". Thesis, Bordeaux 1, 2008. http://www.theses.fr/2008BOR13695/document.
Texto completo da fonteA large variety of curcuminoids Cs and tetrahydrocurcuminoids THCs was synthesized and their antioxidant properties were studied in detail by the radical DPPH° method. For the first time, it was shown that the higher antioxidant properties of THCs compared to their counterparts’ curcuminoids are due to the presence of benzylic hydrogen atoms in THCs. The association of THCs with a biopolymer chitosan, allowed the preparation of films presenting antioxidant and antibacterial properties. Interactions between THCs and chitosan were evidenced by UV-visible absorption spectroscopy. THCs and more particularly tetrahydrocurcumin inhibited development of Fusarium proliferatum fungi in cereals, and limited the production of associated mycotoxins
Pronovost, Stéphanie. "Études des phénomènes photochimiques des nitrates et analyse de la cinétique lors de la photolyse de l'acide nitrique". Mémoire, Université de Sherbrooke, 2012. http://savoirs.usherbrooke.ca/handle/11143/4910.
Texto completo da fonteGuy, Julia. "Photochimiothérapie cutanée : Synthèse de deux molécules hybrides "psoralène-lactone" et études physico-chimiques et photochimiques de leurs interactions avec l'ADN". Université Louis Pasteur (Strasbourg) (1971-2008), 2005. http://www.theses.fr/2005STR13172.
Texto completo da fontePhotochemotherapy is the therapeutic use of radiation in combination with a photosensitizing chemical. Psoralens are well-known photosensitizing drugs which have been employed in photomedicine, in association with UVA radiation, to cure a number of hyperproliferative skin disorders. This therapeutic treatment is generally called PUVA, from psoralen plus UVA light. Nevertheless, the existence of some undesired phototoxic side effects limits the therapeutic use of psoralens. In recent years, many psoralen derivatives have been synthesized with the aim of weakening the phototoxicity on skin. Thus, we report the synthesis and the studies of DNA interactions of two psoralen-lactone heterodimers, which are unable to induce skin phototoxicity on mice and show significant antiproliferative activity on three human cancer cell lines. With the aim of understanding the behaviour of both hybrids toward DNA, we have realized physicochemical and photochemical experiments on heterodimers-DNA complexes. We have shown that, in the dark both hybrids are able to intercalate between DNA base pairs and seem to induce DNA bending. After UV radiation, both compounds exhibit a remarkable ability to give rise to cross-links with double stranded DNA
Buffet, Charles-Henri. "Photoactivatable G-quadruplex ligands : synthesis, activation, reactivity, and biological application". Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASF009.
Texto completo da fonteG-quadruplexes (G4s) are non-canonical four-stranded nucleic acid structures generated by the folding of G-rich sequences in the presence of potassium ions. G4s have been found to form in the human genome (> 10,000) and seem to play a role in the regulation of many cellular processes.The aim of this project is to develop and study trifunctional ligands that can be used in an immunoprecipitation methodology to understand more about G4 accessibility and dynamics by means of a covalent association between the G4 ligand and the G4 structure. These ligands are composed of i) the PDC core able to interact selectively with G-quadruplexes, ii) a photoactivatable moiety (benzophenone, benzyl and aliphatic diazirine, and aryl azide) able to trap covalently G-quadruplexes, and iii) a terminal alkyne for post-covalent binding functionalisation by CuAAC reaction.The first part describes the synthesis and the biophysical and biochemical studies of the two new families of photoactivatable G4 ligands (in-line and branched compounds). The conservation of the specificity of PDC toward G4s was evaluated by FRET-melting and G4-FID assays. Their ability to generate a covalent bond with the G4 structures was assessed by denaturing gel electrophoresis and the identification of the alkylation sites determined by both chemical and enzymatic sequencing experiments.The second part describes the photochemical studies performed in the presence of mimic prototypes. The nature of the reactive intermediates was studied by Laser Flash photolysis. Finally, photoreactivity was studied in the presence of different nucleosides and generated adducts were characterised by NMR
Mercier, Régis. "Synthèse de polysiloxanes photosensibles : étude photochimique". Lille 1, 1985. http://www.theses.fr/1985LIL10044.
Texto completo da fontePichette, Simon. "Étude des possibilités et des limitations des réarrangements photochimiques et thermiques dérivés d'acide hydroxamiques cycliques et synthèse formelle de la géphyrotoxine 287C impliquant le réarrangement photochimique de N-chlorolactame". Thèse, Université de Sherbrooke, 2013. http://hdl.handle.net/11143/6561.
Texto completo da fonteSchaming, Delphine. "Assemblages hybrides porphyrines – polyoxométallates : étude électrochimique, photochimique et photocatalytique". Phd thesis, Université Paris Sud - Paris XI, 2010. http://tel.archives-ouvertes.fr/tel-00714499.
Texto completo da fonteGöttle, Adrien. "Étude théorique de propriétés photophysiques et photochimiques de complexes de ruthénium". Phd thesis, Université Paul Sabatier - Toulouse III, 2013. http://tel.archives-ouvertes.fr/tel-00957277.
Texto completo da fonteIojoiu, Cristina. "Synthèse et caractérisation d'oligosiloxanes fonctionnalisés : étude de leur réticulation par voie photochimique". Montpellier 2, 2001. http://www.theses.fr/2001MON20155.
Texto completo da fonteMeyer, Martine. "Étude photophysique et photochimique de colorants styréniques en relation avec leur efficacité laser". Paris 11, 1989. http://www.theses.fr/1989PA112050.
Texto completo da fonteThe photophysical and photochemical properties of two styrenes dyes : 4-dicyanomethylene-2-methyl-6-p-dimethylamino-styryl-4H-pyran (DCM) and 7-dimethylamino-3-(-p-formylstyryl)-1,4-benzoaxine-2-one (DFSBO) have been studied. These molecules have electron acceptor groups which give to their fluorescent excited state a charge transfer state character. The red shifts of the absorption and fluorescence spectra in polar solvents and the large Stokes shift related to the increase of the dipole moment from the ground state to the singlet excited state have been fully characterised. The absorption spectra of the first excited singlet and triplet states and the quantum yields of the intersystem crossing to the triplet state have been determined. The existence of conformers of the two dyes has been evidenced. The synthesis of DCM leads to the trans isomer which, under light exposure undergoes photoisomerisation to the cis-compound. Their fluorescence lifetimes and the photoisomerisation efficiency are solvent dependent. The DFSBO emission spectra depend greatly on the excitation wavelength. This effect can be explained by the occurence of two rotational conformers one being stabilised by an intramolecular hydrogen bond. The spectral properties of these two molecules enable us to explain why DCM is a very good laser dye whereas DFSBO has a poor laser efficiency
Mazet, Jean-François. "Couleur et qualité des placages de chêne et étude de leur comportement photochimique". Nancy 1, 1988. http://www.theses.fr/1988NAN10393.
Texto completo da fonteMahet, Mathilde. "Processus photochimiques primaires de la photophobie du protozoaire cilié Blepharisma japonicum : étude par pectroscopie ultrarapide". Paris 6, 2005. http://www.theses.fr/2005PA066603.
Texto completo da fonteGalloo, Jean-Claude. "Pollution atmosphérique par les oxydants photochimiques : étude sur le terrain et par simulation numérique au moyen d'un modèle lagrangien". Lille 1, 1985. http://www.theses.fr/1985LIL10138.
Texto completo da fonteCazier, Fabrice. "Mise au point de méthodes d'analyse des polluants organiques et azotés de l'atmosphère : étude par simulation numérique des mécanismes cinétiques représentant le comportement physicochimique de ces espèce". Lille 1, 1990. http://www.theses.fr/1990LIL10053.
Texto completo da fonteKessab, Larbi. "Elaboration et étude photophysique et photochimique de sustèmes aromatiques à deux et trois chromophores". Bordeaux 1, 1993. http://www.theses.fr/1993BOR10553.
Texto completo da fonteSchadkowski, Corinne. "Étude de la pollution photochimique à l'échelle régionale par modélisation eulérienne 3D et mesures spectroradiométriques". Lille 1, 1999. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/1999/50376-1999-245.pdf.
Texto completo da fonteLévi, David. "Synthèse, étude et approche du comportement photochimique complexe et biphotochromes en séries chroménique et oxazinique". Aix-Marseille 2, 2000. http://www.theses.fr/2000AIX22062.
Texto completo da fontePalacin-Saubadu, Chantal. "Photosensibilisation medicamenteuse : étude photochimique et spectroscopique (photo-cidnp) des processus primaires lors de photoréactions de sulfamides". Lille 1, 1990. http://www.theses.fr/1990LIL10014.
Texto completo da fonteDelettre, Éric. "Effets photochimique et photoablatif des lasers sur les plaques d'athérome. Étude in vitro et application in vivo". Paris 7, 1990. http://www.theses.fr/1990PA077189.
Texto completo da fonteJaeger, Christiane. "Photocolorations des pâtes à papier à haut rendement : études photophysique et photochimique de molécules phénoliques non carbonylées, modèles de lignine". Bordeaux 1, 1993. http://www.theses.fr/1993BOR10537.
Texto completo da fonteSanquer-Barrié, Martine. "Étude photophysique et photochimique de chromophores liés à des polymères hydrosolubles : application à la séparation de charges photoinduites". Paris 11, 1989. http://www.theses.fr/1989PA112374.
Texto completo da fonteNoutary, Carole. "Photostabilisation des pâtes à papier à haut rendement blanchies et étude photochimique d'un modèle phénolique de lignine à structure stilbénique". Bordeaux 1, 1994. http://www.theses.fr/1994BOR10510.
Texto completo da fonteLoaiza, Ambuludi Silvia, e Ambuludi Silvia Loaiza. "Étude des propriétés physiques et du comportement mécanique des Basaltes : étude cinétique, mécanistique et toxicologique de l'oxydation dégradante de l'Ibuprofène par l'oxydation avancée électrochimique et photochimique". Phd thesis, Université Paris-Est, 2012. http://tel.archives-ouvertes.fr/tel-00807532.
Texto completo da fonteLoaiza, Ambuludi Silvia. "Étude des propriétés physiques et du comportement mécanique des Basaltes : étude cinétique, mécanistique et toxicologique de l'oxydation dégradante de l'Ibuprofène par l'oxydation avancée électrochimique et photochimique". Thesis, Paris Est, 2012. http://www.theses.fr/2012PEST1145/document.
Texto completo da fonteThe first part of this thesis is focused on the remediation of waters contaminated with persistent organic pollutants, in particular pharmaceutical products. Alternative technologies such as the advanced oxidation processes (AOPs), which based on the generation of hydroxyl radicals OH, were applied to the degradation and/or mineralization of a pollutant drug, ibuprofen, in aqueous medium. We chose this pollutant as a model molecule to study due to its large volume of prescription and to its proved presence in the effluents of sewage plants and natural waters. The main objective of this work was the optimization of operational parameters of the applied AOPs. The concentration of H2O2 and Fe2+ reagents ratio to generate hydroxyl radicals for photo-Fenton process, and supporting electrolyte concentration (and the nature) and the applied current for both electro-Fenton and anodic oxidation processes. The oxidation and mineralization kinetics of the ibuprofen were studied and the absolute rate constant for the oxidative degradation of ibuprofen was determined by the competition kinetic method, being 3,84 109 M-1s-1. Toxicity tests of the drug solutions during the anodic oxidation process were carried out by the Microtox method. Our results show that these methods are effective for the degradation of this pharmaceutical product from water. Ibuprofen was completely degraded and the organic matter was almost completely mineralized after the application of these processes. The second part of the thesis includes an experimental study of the physical properties (at different scales) and the mechanical behavior of basaltic rocks. We studied the mechanical behavior and the failure modes of a porous basalt from Azores. Results were acquired under triaxial compression experiments on water saturated samples at room temperature. This basalt presented two modes of deformation. At low confining pressure, the samples exhibited a brittle mechanical behavior and a localized deformation (shear band). For higher confining pressure, this basalt showed a ductile behavior and localized compactions (compaction bands). The mechanical data allows us to plot the full yield surface for the porous basalt. The quantification of the physical properties of two types of basalts from the Galapagos was performed at room temperature and pressure. In order to study the effect of cracking on the physical properties of these basalts, samples were subjected to thermal treatments to induce thermal crack damage. Finally for the less porous basalt, measures of wave velocities under the pressure at which it is subjected in depth were acquired. The obtained results and the following application of models with them allow quantifying the density of initial cracks and of those induced by thermal treatments, as well as quantifying the aspect ratio of cracks. The studied physical properties led to better understand the role of the pore network of the rock in these physical properties. This laboratory study was necessary for the interpretation of data collected in situ by seismic refraction method
Becker, Christian. "Systèmes polymérisables à faible retrait et études de matériaux pour la stéréolithographie à laser CO2". Vandoeuvre-les-Nancy, INPL, 1994. http://docnum.univ-lorraine.fr/public/INPL_T_1994_BECKER_C.pdf.
Texto completo da fonteRahal, Gaspar Virginie. "Étude de la réactivité photochimique de photosensibilisateurs avec les acides aminés et les protéines en vue d'applications pour la thérapie photodynamique anticancéreuse". Toulouse 3, 2014. http://thesesups.ups-tlse.fr/2431/.
Texto completo da fonteFirst pterins, endogenous UVA -photosensitizers, are heterocyclic organic compounds. They are mainly enzymatic cofactor and are involved in key biological responses such as melanin biosynthesis. They are found at abnormally high levels in certain diseases such as vitiligo. The role of pterins in this disease remains to be determined. In this context, we studied the photosensitisation of the tryptophan (Trp) by pterin under UV-A irradiation. The results obtained by UV-Visible spectroscopy, high performance liquid chromatography and electron paramagnetic resonance (EPR) revealed that trp may be oxidized via two different pathways i) photo-induced electron transfer leading to the formation of a radical cation tryptophan and the radical anion pterin ii) the production of singlet oxygen. This reactivity of pterins with amino acids may contribute to skin depigmentation process in vitiligo. In a second part, we have studied amino acids photosensitisation by ruthenium (II). Due to their versatile photoredox properties, these compounds can react with biological targets by different photochemical mechanisms. In our work we have demonstrated by flash photolysis and EPR Investigations, the involvement of an electron transfer between the ruthenium complex trisbipyrazine ([Ru(Bpz)3]2+) in the excited state and trp leading to the formation of the mono reduced complex and radical cation trp. Mass spectrometry analysis of this reaction revealed the formation of photo-adducts between [Ru(Bpz)3]2+ and Trp free or in the tripeptide Gly-Trp-Glu and allow us to propose some structures. All of these results led us to focus our research into the synthesis of new ruthenium complexes able to selectively inhibit DNA polymerases via a photo-induced electron transfer. In cells, these enzymes play a key role in cell proliferation. The development of such photo-activable inhibitors would be an asset for the photodynamic therapy. For this purpose we have decided to conjugate a high photo-ozidizing ruthenium complex with oligonucleotides selectively recognized DNA polymerase. The synthesis of such complex is still under development
Labra-Vasquez, Pablo. "Conception, synthèse et étude photochimiques de complexes de ruthénium nitrosyle et de composés carborane-BODIPY pour des applications potentielles comme agent thérapeutique et l'imagerie cellulaire". Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30201.
Texto completo da fontePhotoactivated chemotherapy (PACT) is a therapeutic approach based on the photo-induced release of a toxic molecule capable of producing cell death; as the toxicity of the molecule is triggered locally by light, PACT provides an elegant way to destroy cancer cells without damaging nearby healthy tissues. In this context, our research group has been developing ruthenium nitrosyl complexes (RuNO) with polypyridyl ligands which are capable of releasing NO• via two-photon absorption (TPA). In Chapter I, after reviewing the state of the art of PACT, the evaluation of the influence of the introduction of a thienyl ring in the polypyridyl ligand is described as a strategy to improve the two-photon absorption cross sections of the complexes. Chapter II focuses on Boron Neutron Capture Therapy (BNCT), a type of radiation therapy in which the ionizing energy that produces cell death is generated by the fission of 10B nuclei after irradiation with low energy neutrons. Because cell death is restricted to boron-enriched cells, BNCT provides the ability to selectively treat tumors, minimizing damage to nearby healthy tissues. Due to their high boron contents, carboranes (polyhedral carbon-boron clusters) are ideal candidates for BNCT. After a comprehensive analysis of the state of the art of BNCT, we present the synthesis, chemical and photochemical characterization, and the study of cell entry on HeLa cells for a group of carboranes functionalized with BODIPY fluorophores. The results show that lipophilicity and the dipole moment have an important influence on the ease with which the fluorophores studied permeate to the intracellular media, thus providing an explanation for the divergent cellular permeability that this type of compounds usually show
Hecka, Audrey. "Caractérisation par spectrométrie de masse d'extraits de millepertuis potentiellement utilisables en photodiagnostic et photothérapie des cancers : étude de leurs propriétés photochimiques en solution et en milieu cellulaire". Thesis, Metz, 2009. http://www.theses.fr/2009METZ052S/document.
Texto completo da fontePhotodynamic therapy (PDT) combines light with a drug called photosensitizing agent, which preferentially accumulates in cancerous cells. Irradiated with visible light, this photosensitizing agent generates singlet oxygen (1O2) and radicals that demonstrate cell toxicity. Fluorescence of this drug also allows diagnosing neoplasic lesions: this is photodynamic diagnosis (PDD).St John’s Wort extracts, mainly known for their antidepressant activity, also contain photoactive compounds, including hypericin which has been extensively studied for PDT and PDD. However, producing this molecule in large amounts is expensive and its use is restricted by a poor solubility in physiological medium. In this context, the present study deals with determining in what extent St John’s Wort extracts could be useful for PDT and PDD. Flowers that were used in this work were firstly in situ-analyzed by mass spectrometry in order to characterized photoactive compounds at the level of structures involved in their biosynthesis. These compounds were then extracted by organic solvent and the resulting mixture subjected to singlet oxygen production measurements under laser illumination. Qualitative analysis of the extracts was then performed either by Laser Desorption/Ionization or Electrospray Ionization coupled with Mass Spectrometry (TOF and FTICR). Finally, their behavior in cellular medium (bladder cancer) was investigated in terms of dark cytotoxicity, intracellular accumulation of photoactive compounds, phototoxicity and characterization of compounds absorbed by cells
Diagne, Mababa. "Étude de dégradation par oxydation avancée électrochimique et photochimique de pesticides organophosphorés : application à la dégradation du parathion méthyle et de l'acéphate en mileu aqueux". Marne-la-Vallée, 2006. http://www.theses.fr/2006MARN0304.
Texto completo da fonteThe degradation of methyl parathion and acephate, both organophophorus insecticides, was studied in acid medium by the electro-Fenton and photo Fenton processes. The aromatic and aliphatic reaction intermediates of its degradation were highlighted. The evolution of the chemical composition of the methyl parathion and its aromatic and carboxylic acid derivatives were determined and followed by high performance liquid chromatography. The identification and evolution of the intermediates during electrolysis permitted to propose a mineralization of the insecticides under examination. The mineralization efficiency was evaluated by the total organic carbon (COT) measurements with different pH in different media in order to highlight their effect on the electro-Fenton process. In the photo-Fenton process, the influence of the concentration ratio (H2O2/Fe3+) of the reagent was studied to determine the optimal value for the best mineralization efficiency. These two processes show, in all the cases, their capacity to mineralize toxic organic pollutants, in fact, the pesticides. In addition, the formation and decomposition rate of H2O2 and Fe3+ during electro-Fenton process in perchloric medium at pH = 3 have been described in theoretical way for comparison to the experimental results obtained. Decomposition of Fenton’s reagent (Fe3+, H2O2) for the current intensities of 60 and 100 mA have been described theoretically
Saghbini, Samar. "Étude photophysique de la cinétique de formation de complexes". Vandoeuvre-les-Nancy, INPL, 1994. http://www.theses.fr/1994INPL032N.
Texto completo da fonteDorion, Catherine. "Étude de catalyseurs déposés pour réacteur photocatalytique de traitement des eaux". Vandoeuvre-les-Nancy, INPL, 1996. http://docnum.univ-lorraine.fr/public/INPL_T_1996_DORION_C.pdf.
Texto completo da fonteZimmermann, Valérie. "Simulation numérique de la formation de l'ozone et des oxydants photochimiques dans la troposphère : validation d'un modèle physicochimique et étude des caractéristiques structurales et cinétiques des mécanismes chimiques associés". Lille 1, 1989. http://www.theses.fr/1989LIL10074.
Texto completo da fonteLelimousin, Mickaël. "Traitement des interactions électrostatiques dans les systèmes moléculaires : étude par simulation numérique de protéines fluorescentes". Grenoble 1, 2009. http://www.theses.fr/2009GRE10075.
Texto completo da fonteReaction processes in biological systems are henceforth modeled by more and more advanced quantum mechanics (QM) methods coupled with force fields of molecular mechanics (MM). This improvement involves problems in the usual treatment of the QM/MM electrostatic interactions. In the first part of the thesis, we have developed a more consistent approach for the calculation of these interactions. In a second part, we have applied some computational methods to fluorescent proteins. A molecular dynamics study has revealed weak van der Waals interactions which control the improved fluorescence for Cerulean, a variant of ECFP (Enhanced Cyan Fluorescent Protein). We have also investigated the photoconversion mechanism of the fluorescent protein EosFP using predictive QM/MM potentials for excited states. Finally, thermodynamic stability of different structures in IrisFP has been estimated. These molecular modeling studies improve our knowledge about fluorescent proteins in order to develop more advanced highlighters for cell imaging
Li, Wenjing. "Nucléation non-photochimique induite par laser (NPLIN) : Contribution au mécanisme de nucléation à travers des études expérimentales sur le sulfathiazole, L-acide glutamique et la glycine et la modélisation de quelques petites molécules". Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLC019.
Texto completo da fonteThis thesis concerns the demonstration of the feasibility of Non-Photochemical Laser Induced Nucleation (NPLIN) of some organic pharmaceutical compounds. Using our experimental results and those obtained in literature together with ab initio theoretical calculations we have been able to discuss the mechanism of the NPLIN method.This thesis presents a new experimental set-up developed at CentraleSupelec and dedicated to perform NPLIN experiments. NPLIN experiments on sulfathiazole (STZ), l-glutamic acid (LGA) and glycine (GLY) have been carried out to examine the impact of laser parameters and solution supersaturation on their crystallization. Experimental results show that crystals of STZ, LGA and GLY have been obtained by means of NPLIN. For these compounds, nucleation efficiency increases with laser power density and solution supersaturation. A new index Ind50 corresponding to the couple (energy density/supersaturation) where 50% of nucleation is teached, has been defined. Its behavior has been discussed. It was found that laser induced STZ crystal number depends almost linearly on exposure duration. Moreover, for STZ and GLY, a dependance of laser induced crystal polymorph on laser polarization has been found. Another new index Det(A), has been used for characterization of the impact of the polymorphism. Ab initio quantum computations using Gaussian09, provided an interaction energy estimate for different dimers in different polymorphs of STZ, LGA, GLY, l-histidine (LH) and urea. Packing mode in pre-existing clusters is predicted in agreement with interaction energy determinations. Correlation analysis between packing symmetry and experimental results, shed new light on the Kerr effect hypothesis relative to the impact of laser polarization on polymorphism
Wilson, Flore Adjélé. "Étude du mécanisme de photoprotection lié à l’Orange Carotenoid Protein et ses homologues chez les cyanobactéries". Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS503/document.
Texto completo da fontePhotosynthetic organisms use light energy from the sun in order to perform photosynthesis and to convert solar energy into chemical energy. Absorbance of excess light energy beyond what can be consumed in photosynthesis is dangerous for these organisms. Reactive oxygen species (ROS) are formed at the reaction centers and collecting light antennas inducing photooxidative damage which can lead to cell death. In cyanobacteria, one of these photoprotective mechanisms consists to reduce the amount of energy arriving to the reaction centers by thermal dissipation of the excess absorbed energy. Energy dissipation is accompanied by a decrease of Photosystem II-related fluorescence emission called non-photochemical quenching (NPQ). The soluble Orange Carotenoid Protein (OCPo) is essential for this photoprotective mechanism. The OCP is the first photo-active protein with a carotenoid known as light intensity sensor and acts as energy quencher of the phycobilisome (PB), the extra-membrane antenna of cyanobacteria. Structural changes occur when the OCPo absorbs a strong blue-green light leading to a red active form (OCPr). The N-terminal domain of OCPr burrows into the two external trimers of the core basal APC cylinders of the PB and increases thermal energy dissipation at the level of antenna. The OCP has an additional function in photoprotection as oxygen singlet quencher protecting cells from oxidative stress. Under low light conditions, to recover the full antenna capacity, a second protein is needed, the "Fluorescence Recovery Protein" (FRP), whose role is to detach the OCPr from the PB and accelerate its conversion into an inactive OCPo. In this manuscript, I will review the knowledge about the OCP, since the discovery of the mechanism and its characterization to the latest advances on the OCP-related-NPQ mechanism in cyanobacteria
Jennesson, Didier. "Étude de l'influence des phénomènes de couche limite sur le fonctionnement de photoréacteurs". Vandoeuvre-les-Nancy, INPL, 1994. http://www.theses.fr/1994INPL114N.
Texto completo da fonteSchapman, Fanny. "Fonctionnalisation et étude de la réticulation d'un polybutadiène hydroxy téléchélique". Rouen, 1996. http://www.theses.fr/1996ROUES035.
Texto completo da fonteEl-rachidi, Mariam. "Étude cinétique et mécanistique des réactions hétérogènes du folpel et du dimethomorphe avec l'ozone et les radicaux OH. Photooxydation homogène des composés morpholiniques avec les radicaux OH". Thesis, Reims, 2012. http://www.theses.fr/2012REIMS011.
Texto completo da fonteThe research study discussed in this thesis concerns the determination of the kinetic rate constants of the heterogeneous degradation of pesticides folpet and dimethomorph by ozone and OH-radicals using the technique of a simulation chamber coupled to a GC/MS analytical system. The study also involves the identification of the degradation products of the analyzed compound in the condensed phase using SPME/GC/MS. The heterogeneous OH and O3-reactivities of the identified degradation product of dimethomorph, (4-chlorophenyl)(3,4-dimethoxyphenyl)methanone (CPMPM), are also evaluated experimentally. The obtained results show that the rate constant values of the analytes are in the order of 10-20-10-19 and 10-14-10-12 cm3.molecule-1.s-1 relative to heterogeneous O3 and OH-oxidation, respectively. Such values implicate tropospheric life-times that vary from a few days to several months, meaning that these compounds are relatively persistent and may be transported to regions far from their point of application.The UV-absorption spectra and homogeneous OH-reactivities of the expected degradation product of dimethomorph in the gas phase, N-formylmorpholine (NFM), and two other gaseous compounds, morpholine and N-acetylmorpholne (NAM) are also studied. The results show that these compounds are not susceptible to photolysis in the atmosphere and that they exhibit strong reactivity towards OH-radicals. Generally speaking, their atmospheric life-times are in the order of a few hours and thus they are non-persistent
Marcot, Bonnet Laurence. "Synthèses, études physico-chimiques, photopolymérisation et mesures optiques de métallomésogènes colonnaires hexagonaux". Université Joseph Fourier (Grenoble), 1995. http://www.theses.fr/1995GRE10112.
Texto completo da fonteRoustan, Audrey. "Génotoxicité du glyphosate, de l'atrazine et de leurs produits de dégradation seuls et en mélanges : étude de l'effet protecteur d'un cocktail de plantes". Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM5066.
Texto completo da fonteGlyphosate, atrazine, and their main degradation products (desethyl-atrazine or DEA, and the amino methyl phosphoric acid or AMPA) are among the most widely used pesticides in the world and in France. They are found in large quantities in several environmental matrices but also in food and drinking water.The aim of our work was to evaluate the genotoxicity and mutagenicity in vitro and in vivo of these four pesticides, alone and in mixtures, and to study the protective effects of a mixture composed with extracts of anti-mutagenic plants (Berberis vulgaris, Arctium lappa and Taraxacum officinalis) (DIG) on the genotoxicity of the mixture of four pesticides.The results of our in vitro study showed that the genotoxic potential of pesticides depends on their physico-chemical environment, and that mixtures of pesticides can reveal genotoxic properties more important than those predictable during the exposure to individual molecules, with occurrence of a cocktail effect. The results of our in vivo study clearly established the powerful genotoxic and mutagenic activity of the mixture of four pesticides. They highlighted the cocktail effects that may occur in mixtures of pesticides, underlining the limits of conventional toxicological strategies based on an individual assessment of the molecules. We have shown that brain cells are the main target of pesticides, probably related to a significant sensitivity to oxidative stress. In the third part, we demonstrated the protective effects of DIG on the genotoxicity and mutagenicity of the mixture of four pesticides
Zissi, Sophia. "Microstéréophotolithographie". Vandoeuvre-les-Nancy, INPL, 1995. http://www.theses.fr/1995INPL039N.
Texto completo da fonteCoutterez, Claire. "Synthèse, caractérisation et étude des propriétés d'oligomères et polymères hétéroarylène vinylènes". Grenoble INPG, 1998. http://www.theses.fr/1998INPG0163.
Texto completo da fonteChaabouni, Henda. "Étude par spectroscopie infrarouge de l'ozone et du dioxyde de soufre adsorbés sur la surface de la glace ou piégés dans son volume entre 10 et 170 k. Effets d'irradiation à 266 nm sur le mélange O3 + SO2 piégé en matrice d'argon ou dans la glace". Paris 6, 2001. http://www.theses.fr/2001PA066230.
Texto completo da fontePapazia, Mariam Eugénie. "Comportement de molécules biocides thiocyanées dans l'environnement : étude de leur dégradation : décomposition du sulfure de diméthyle, modèle de molécule soufrée, légère, malodorante : interactions de surface DMS-TiO2". Université Joseph Fourier (Grenoble), 1995. http://www.theses.fr/1995GRE10172.
Texto completo da fonteDenis, Isabelle. "Photodégradation des composés organiques volatils biogéniques dans l'atmosphère : étude de la réactivité du (beta)-pinène vis à vis des radicaux hydroxyles ; cas de la réactivité en milieu hétérogène". Université Joseph Fourier (Grenoble), 1995. http://www.theses.fr/1995GRE10129.
Texto completo da fontePerny, Sébastien. "Alignement de cristaux liquides par irradiation en lumière linéairement polarisée de film minces de polymères photoréticulables". Cachan, Ecole normale supérieure, 1998. http://www.theses.fr/1998DENS0042.
Texto completo da fonteAit, Ali Nadia. "Étude des mécanismes d'inhibition du transport des électrons photosynthétiques induite par les xénobiotiques affectant les réactions photochimiques du photosystème II". Thèse, 2008. http://www.archipel.uqam.ca/873/1/D1623.pdf.
Texto completo da fonteEl-Rachidi, Mariam. "Étude cinétique et mécanistique des réactions hétérogènes du folpel et du dimethomorphe avec l'ozone et les radicaux OH. Photooxydation homogène des composés morpholiniques avec les radicaux OH". Thesis, 2012. http://www.theses.fr/2012REIMS011/document.
Texto completo da fonteThe research study discussed in this thesis concerns the determination of the kinetic rate constants of the heterogeneous degradation of pesticides folpet and dimethomorph by ozone and OH-radicals using the technique of a simulation chamber coupled to a GC/MS analytical system. The study also involves the identification of the degradation products of the analyzed compound in the condensed phase using SPME/GC/MS. The heterogeneous OH and O3-reactivities of the identified degradation product of dimethomorph, (4-chlorophenyl)(3,4-dimethoxyphenyl)methanone (CPMPM), are also evaluated experimentally. The obtained results show that the rate constant values of the analytes are in the order of 10-20-10-19 and 10-14-10-12 cm3.molecule-1.s-1 relative to heterogeneous O3 and OH-oxidation, respectively. Such values implicate tropospheric life-times that vary from a few days to several months, meaning that these compounds are relatively persistent and may be transported to regions far from their point of application.The UV-absorption spectra and homogeneous OH-reactivities of the expected degradation product of dimethomorph in the gas phase, N-formylmorpholine (NFM), and two other gaseous compounds, morpholine and N-acetylmorpholne (NAM) are also studied. The results show that these compounds are not susceptible to photolysis in the atmosphere and that they exhibit strong reactivity towards OH-radicals. Generally speaking, their atmospheric life-times are in the order of a few hours and thus they are non-persistent